Using the formula t=root of 2h/g then where h=28 and g=9.8 then substitute so the answer is 2.4seconds
Answer:

Explanation:
Amplitude is 35/2=17.5
Midline= Distance from ground + Amplitude = 17.5+3= 20.5
Period is time taken to finish 6 minutes
2π/b=T
2π/b=6
b=π/3

Lower the resistance to sliding.
The old electricity meters with disk using sapphire bearings for friction to be minimal to not aggravate metering